/
gconv_scan.go
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/
gconv_scan.go
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// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
//
// This Source Code Form is subject to the terms of the MIT License.
// If a copy of the MIT was not distributed with this file,
// You can obtain one at https://github.com/gogf/gf.
package gconv
import (
"database/sql"
"reflect"
"github.com/gogf/gf/v2/errors/gcode"
"github.com/gogf/gf/v2/errors/gerror"
"github.com/gogf/gf/v2/internal/utils"
"github.com/gogf/gf/v2/os/gstructs"
)
// Scan automatically checks the type of `pointer` and converts `params` to `pointer`. It supports `pointer`
// with type of `*map/*[]map/*[]*map/*struct/**struct/*[]struct/*[]*struct` for converting.
//
// It calls function `doMapToMap` internally if `pointer` is type of *map for converting.
// It calls function `doMapToMaps` internally if `pointer` is type of *[]map/*[]*map for converting.
// It calls function `doStruct` internally if `pointer` is type of *struct/**struct for converting.
// It calls function `doStructs` internally if `pointer` is type of *[]struct/*[]*struct for converting.
func Scan(params interface{}, pointer interface{}, mapping ...map[string]string) (err error) {
var (
pointerType reflect.Type
pointerKind reflect.Kind
pointerValue reflect.Value
)
if v, ok := pointer.(reflect.Value); ok {
pointerValue = v
pointerType = v.Type()
} else {
pointerValue = reflect.ValueOf(pointer)
pointerType = reflect.TypeOf(pointer) // Do not use pointerValue.Type() as pointerValue might be zero.
}
if pointerType == nil {
return gerror.NewCode(gcode.CodeInvalidParameter, "parameter pointer should not be nil")
}
pointerKind = pointerType.Kind()
if pointerKind != reflect.Ptr {
if pointerValue.CanAddr() {
pointerValue = pointerValue.Addr()
pointerType = pointerValue.Type()
pointerKind = pointerType.Kind()
} else {
return gerror.NewCodef(
gcode.CodeInvalidParameter,
"params should be type of pointer, but got type: %v",
pointerType,
)
}
}
// Direct assignment checks!
var (
paramsType reflect.Type
paramsValue reflect.Value
)
if v, ok := params.(reflect.Value); ok {
paramsValue = v
paramsType = paramsValue.Type()
} else {
paramsValue = reflect.ValueOf(params)
paramsType = reflect.TypeOf(params) // Do not use paramsValue.Type() as paramsValue might be zero.
}
// If `params` and `pointer` are the same type, the do directly assignment.
// For performance enhancement purpose.
var (
pointerValueElem = pointerValue.Elem()
)
if pointerValueElem.CanSet() && paramsType == pointerValueElem.Type() {
pointerValueElem.Set(paramsValue)
return nil
}
// Converting.
var (
pointerElem = pointerType.Elem()
pointerElemKind = pointerElem.Kind()
keyToAttributeNameMapping map[string]string
)
if len(mapping) > 0 {
keyToAttributeNameMapping = mapping[0]
}
switch pointerElemKind {
case reflect.Map:
return doMapToMap(params, pointer, mapping...)
case reflect.Array, reflect.Slice:
var (
sliceElem = pointerElem.Elem()
sliceElemKind = sliceElem.Kind()
)
for sliceElemKind == reflect.Ptr {
sliceElem = sliceElem.Elem()
sliceElemKind = sliceElem.Kind()
}
if sliceElemKind == reflect.Map {
return doMapToMaps(params, pointer, mapping...)
}
return doStructs(params, pointer, keyToAttributeNameMapping, "")
default:
return doStruct(params, pointer, keyToAttributeNameMapping, "")
}
}
// ScanList converts `structSlice` to struct slice which contains other complex struct attributes.
// Note that the parameter `structSlicePointer` should be type of *[]struct/*[]*struct.
//
// Usage example 1: Normal attribute struct relation:
//
// type EntityUser struct {
// Uid int
// Name string
// }
//
// type EntityUserDetail struct {
// Uid int
// Address string
// }
//
// type EntityUserScores struct {
// Id int
// Uid int
// Score int
// Course string
// }
//
// type Entity struct {
// User *EntityUser
// UserDetail *EntityUserDetail
// UserScores []*EntityUserScores
// }
//
// var users []*Entity
// ScanList(records, &users, "User")
// ScanList(records, &users, "User", "uid")
// ScanList(records, &users, "UserDetail", "User", "uid:Uid")
// ScanList(records, &users, "UserScores", "User", "uid:Uid")
// ScanList(records, &users, "UserScores", "User", "uid")
//
// Usage example 2: Embedded attribute struct relation:
//
// type EntityUser struct {
// Uid int
// Name string
// }
//
// type EntityUserDetail struct {
// Uid int
// Address string
// }
//
// type EntityUserScores struct {
// Id int
// Uid int
// Score int
// }
//
// type Entity struct {
// EntityUser
// UserDetail EntityUserDetail
// UserScores []EntityUserScores
// }
//
// var users []*Entity
// ScanList(records, &users)
// ScanList(records, &users, "UserDetail", "uid")
// ScanList(records, &users, "UserScores", "uid")
//
// The parameters "User/UserDetail/UserScores" in the example codes specify the target attribute struct
// that current result will be bound to.
//
// The "uid" in the example codes is the table field name of the result, and the "Uid" is the relational
// struct attribute name - not the attribute name of the bound to target. In the example codes, it's attribute
// name "Uid" of "User" of entity "Entity". It automatically calculates the HasOne/HasMany relationship with
// given `relation` parameter.
//
// See the example or unit testing cases for clear understanding for this function.
func ScanList(structSlice interface{}, structSlicePointer interface{}, bindToAttrName string, relationAttrNameAndFields ...string) (err error) {
var (
relationAttrName string
relationFields string
)
switch len(relationAttrNameAndFields) {
case 2:
relationAttrName = relationAttrNameAndFields[0]
relationFields = relationAttrNameAndFields[1]
case 1:
relationFields = relationAttrNameAndFields[0]
}
return doScanList(structSlice, structSlicePointer, bindToAttrName, relationAttrName, relationFields)
}
// doScanList converts `structSlice` to struct slice which contains other complex struct attributes recursively.
// Note that the parameter `structSlicePointer` should be type of *[]struct/*[]*struct.
func doScanList(
structSlice interface{}, structSlicePointer interface{}, bindToAttrName, relationAttrName, relationFields string,
) (err error) {
var (
maps = Maps(structSlice)
)
if len(maps) == 0 {
return nil
}
// Necessary checks for parameters.
if bindToAttrName == "" {
return gerror.NewCode(gcode.CodeInvalidParameter, `bindToAttrName should not be empty`)
}
if relationAttrName == "." {
relationAttrName = ""
}
var (
reflectValue = reflect.ValueOf(structSlicePointer)
reflectKind = reflectValue.Kind()
)
if reflectKind == reflect.Interface {
reflectValue = reflectValue.Elem()
reflectKind = reflectValue.Kind()
}
if reflectKind != reflect.Ptr {
return gerror.NewCodef(
gcode.CodeInvalidParameter,
"structSlicePointer should be type of *[]struct/*[]*struct, but got: %v",
reflectKind,
)
}
reflectValue = reflectValue.Elem()
reflectKind = reflectValue.Kind()
if reflectKind != reflect.Slice && reflectKind != reflect.Array {
return gerror.NewCodef(
gcode.CodeInvalidParameter,
"structSlicePointer should be type of *[]struct/*[]*struct, but got: %v",
reflectKind,
)
}
length := len(maps)
if length == 0 {
// The pointed slice is not empty.
if reflectValue.Len() > 0 {
// It here checks if it has struct item, which is already initialized.
// It then returns error to warn the developer its empty and no conversion.
if v := reflectValue.Index(0); v.Kind() != reflect.Ptr {
return sql.ErrNoRows
}
}
// Do nothing for empty struct slice.
return nil
}
var (
arrayValue reflect.Value // Like: []*Entity
arrayItemType reflect.Type // Like: *Entity
reflectType = reflect.TypeOf(structSlicePointer)
)
if reflectValue.Len() > 0 {
arrayValue = reflectValue
} else {
arrayValue = reflect.MakeSlice(reflectType.Elem(), length, length)
}
// Slice element item.
arrayItemType = arrayValue.Index(0).Type()
// Relation variables.
var (
relationDataMap map[string]interface{}
relationFromFieldName string // Eg: relationKV: id:uid -> id
relationBindToFieldName string // Eg: relationKV: id:uid -> uid
)
if len(relationFields) > 0 {
// The relation key string of table filed name and attribute name
// can be joined with char '=' or ':'.
array := utils.SplitAndTrim(relationFields, "=")
if len(array) == 1 {
// Compatible with old splitting char ':'.
array = utils.SplitAndTrim(relationFields, ":")
}
if len(array) == 1 {
// The relation names are the same.
array = []string{relationFields, relationFields}
}
if len(array) == 2 {
// Defined table field to relation attribute name.
// Like:
// uid:Uid
// uid:UserId
relationFromFieldName = array[0]
relationBindToFieldName = array[1]
if key, _ := utils.MapPossibleItemByKey(maps[0], relationFromFieldName); key == "" {
return gerror.NewCodef(
gcode.CodeInvalidParameter,
`cannot find possible related table field name "%s" from given relation fields "%s"`,
relationFromFieldName,
relationFields,
)
} else {
relationFromFieldName = key
}
} else {
return gerror.NewCode(
gcode.CodeInvalidParameter,
`parameter relationKV should be format of "ResultFieldName:BindToAttrName"`,
)
}
if relationFromFieldName != "" {
// Note that the value might be type of slice.
relationDataMap = utils.ListToMapByKey(maps, relationFromFieldName)
}
if len(relationDataMap) == 0 {
return gerror.NewCodef(
gcode.CodeInvalidParameter,
`cannot find the relation data map, maybe invalid relation fields given "%v"`,
relationFields,
)
}
}
// Bind to target attribute.
var (
ok bool
bindToAttrValue reflect.Value
bindToAttrKind reflect.Kind
bindToAttrType reflect.Type
bindToAttrField reflect.StructField
)
if arrayItemType.Kind() == reflect.Ptr {
if bindToAttrField, ok = arrayItemType.Elem().FieldByName(bindToAttrName); !ok {
return gerror.NewCodef(
gcode.CodeInvalidParameter,
`invalid parameter bindToAttrName: cannot find attribute with name "%s" from slice element`,
bindToAttrName,
)
}
} else {
if bindToAttrField, ok = arrayItemType.FieldByName(bindToAttrName); !ok {
return gerror.NewCodef(
gcode.CodeInvalidParameter,
`invalid parameter bindToAttrName: cannot find attribute with name "%s" from slice element`,
bindToAttrName,
)
}
}
bindToAttrType = bindToAttrField.Type
bindToAttrKind = bindToAttrType.Kind()
// Bind to relation conditions.
var (
relationFromAttrValue reflect.Value
relationFromAttrField reflect.Value
relationBindToFieldNameChecked bool
)
for i := 0; i < arrayValue.Len(); i++ {
arrayElemValue := arrayValue.Index(i)
// The FieldByName should be called on non-pointer reflect.Value.
if arrayElemValue.Kind() == reflect.Ptr {
// Like: []*Entity
arrayElemValue = arrayElemValue.Elem()
if !arrayElemValue.IsValid() {
// The element is nil, then create one and set it to the slice.
// The "reflect.New(itemType.Elem())" creates a new element and returns the address of it.
// For example:
// reflect.New(itemType.Elem()) => *Entity
// reflect.New(itemType.Elem()).Elem() => Entity
arrayElemValue = reflect.New(arrayItemType.Elem()).Elem()
arrayValue.Index(i).Set(arrayElemValue.Addr())
}
} else {
// Like: []Entity
}
bindToAttrValue = arrayElemValue.FieldByName(bindToAttrName)
if relationAttrName != "" {
// Attribute value of current slice element.
relationFromAttrValue = arrayElemValue.FieldByName(relationAttrName)
if relationFromAttrValue.Kind() == reflect.Ptr {
relationFromAttrValue = relationFromAttrValue.Elem()
}
} else {
// Current slice element.
relationFromAttrValue = arrayElemValue
}
if len(relationDataMap) > 0 && !relationFromAttrValue.IsValid() {
return gerror.NewCodef(gcode.CodeInvalidParameter, `invalid relation fields specified: "%v"`, relationFields)
}
// Check and find possible bind to attribute name.
if relationFields != "" && !relationBindToFieldNameChecked {
relationFromAttrField = relationFromAttrValue.FieldByName(relationBindToFieldName)
if !relationFromAttrField.IsValid() {
var (
filedMap, _ = gstructs.FieldMap(gstructs.FieldMapInput{
Pointer: relationFromAttrValue,
RecursiveOption: gstructs.RecursiveOptionEmbeddedNoTag,
})
)
if key, _ := utils.MapPossibleItemByKey(Map(filedMap), relationBindToFieldName); key == "" {
return gerror.NewCodef(
gcode.CodeInvalidParameter,
`cannot find possible related attribute name "%s" from given relation fields "%s"`,
relationBindToFieldName,
relationFields,
)
} else {
relationBindToFieldName = key
}
}
relationBindToFieldNameChecked = true
}
switch bindToAttrKind {
case reflect.Array, reflect.Slice:
if len(relationDataMap) > 0 {
relationFromAttrField = relationFromAttrValue.FieldByName(relationBindToFieldName)
if relationFromAttrField.IsValid() {
// results := make(Result, 0)
results := make([]interface{}, 0)
for _, v := range SliceAny(relationDataMap[String(relationFromAttrField.Interface())]) {
item := v
results = append(results, item)
}
if err = Structs(results, bindToAttrValue.Addr()); err != nil {
return err
}
} else {
// Maybe the attribute does not exist yet.
return gerror.NewCodef(gcode.CodeInvalidParameter, `invalid relation fields specified: "%v"`, relationFields)
}
} else {
return gerror.NewCodef(
gcode.CodeInvalidParameter,
`relationKey should not be empty as field "%s" is slice`,
bindToAttrName,
)
}
case reflect.Ptr:
var element reflect.Value
if bindToAttrValue.IsNil() {
element = reflect.New(bindToAttrType.Elem()).Elem()
} else {
element = bindToAttrValue.Elem()
}
if len(relationDataMap) > 0 {
relationFromAttrField = relationFromAttrValue.FieldByName(relationBindToFieldName)
if relationFromAttrField.IsValid() {
v := relationDataMap[String(relationFromAttrField.Interface())]
if v == nil {
// There's no relational data.
continue
}
if utils.IsSlice(v) {
if err = Struct(SliceAny(v)[0], element); err != nil {
return err
}
} else {
if err = Struct(v, element); err != nil {
return err
}
}
} else {
// Maybe the attribute does not exist yet.
return gerror.NewCodef(gcode.CodeInvalidParameter, `invalid relation fields specified: "%v"`, relationFields)
}
} else {
if i >= len(maps) {
// There's no relational data.
continue
}
v := maps[i]
if v == nil {
// There's no relational data.
continue
}
if err = Struct(v, element); err != nil {
return err
}
}
bindToAttrValue.Set(element.Addr())
case reflect.Struct:
if len(relationDataMap) > 0 {
relationFromAttrField = relationFromAttrValue.FieldByName(relationBindToFieldName)
if relationFromAttrField.IsValid() {
relationDataItem := relationDataMap[String(relationFromAttrField.Interface())]
if relationDataItem == nil {
// There's no relational data.
continue
}
if utils.IsSlice(relationDataItem) {
if err = Struct(SliceAny(relationDataItem)[0], bindToAttrValue); err != nil {
return err
}
} else {
if err = Struct(relationDataItem, bindToAttrValue); err != nil {
return err
}
}
} else {
// Maybe the attribute does not exist yet.
return gerror.NewCodef(gcode.CodeInvalidParameter, `invalid relation fields specified: "%v"`, relationFields)
}
} else {
if i >= len(maps) {
// There's no relational data.
continue
}
relationDataItem := maps[i]
if relationDataItem == nil {
// There's no relational data.
continue
}
if err = Struct(relationDataItem, bindToAttrValue); err != nil {
return err
}
}
default:
return gerror.NewCodef(gcode.CodeInvalidParameter, `unsupported attribute type: %s`, bindToAttrKind.String())
}
}
reflect.ValueOf(structSlicePointer).Elem().Set(arrayValue)
return nil
}